A centering and clamping device is known according to DE 102 38 815 B3. It has a closed housing with a drive mechanism that actuates a clamping hook that is active outside the housing. The clamping hook engages through an opening on the housing provided with a seal element. The seal element is referred to as a “slot cover slide”. It is implemented as a spring-loaded closure that follows the movement of the clamping hook. However, since the slot cover slide is only situated on one side of the clamping hook, in spite of the centering mandrel closed on one side, a danger exists that contaminants, such as metal chips or the like, will reach the interior of the housing.